Aquarium UV Sterilizer Use; Choosing & Maintenance

CHOOSING YOUR AQUARIUM UV STERILIZER

The purpose of this article is to provide basic answers to the most common questions asked about the use of a UV Sterilizer in Aquariums

Much of this information is courtesy of:“UV Sterilizer Use & Information, A to Z” This is probably the most in depth and accurate article on the subject of aquarium UV sterilizer use I have read anywhere. The author of the above article is one of the leading authorities on this subject with a considerable amount of hands on experience using and even designing true UV Sterilizers as well as UV Clarifiers which are commonly marketed as UV Sterilizers.

Readers will also note that it is often updated too, making for the most current information.

FREQUENTLY ASKED AQUARIUM (& POND) UV STERILIZER QUESTIONS & ANSWERS:

What is a UV Sterilizer?

A UV Sterilizer is a germicidal filtration device that uses UV-C Sterilization to filter the water resulting in clarification, lower disease pathogens, and removal of oxidizers in the water column resulting in improved Redox in your aquarium or pond.

What can a UV Sterilizer do for my fish tank/ pond?

A correctly installed and well designed TRUE level one or two capable UV Sterilizer can kill most suspended bacteria and many viruses in the water column, while not affecting bacterial colonies in filter media and substrate. As well a UV Sterilizer/Clarifier can clear green/cloudy water in aquariums or ponds. See this link for one source: UV Sterilizer/Clarifiers

A QUALITY UV-C Steriliser also improves the Redox Balance in an aquarium or pond by lowering oxidizers and thus oxidative stress in the water column which in turn improves the fish’ ability to fight disease.

A UV sterilizer aids in the control of parasites such as Ich or Cryptocaryon by improving immune function and disease resistance (via Redox). At very low flows (under 8-12 gph per watt) a UV Sterilizer can more directly aid in parasite control of parasites in the water column.

Unfortunately many UV Sterilizers do not adequately improve Redox balance by lowering oxidizers in the water column that can be dangerous to fish over time. This is due to insufficient 254nm UVC exposure inside the unit from poorly designed units along with incorrect flow time and use of poor UVC generating medium pressure UV bulbs that most lower cost UVs commonly sold by discounters now use so as to keep the price down.

The picture above provides a visual of how a TRUE UV-C Sterilizer breaks down oxidizers, which are negatively charged ions (anions) in the water column. This in turn reduces oxidative stress on fish.

A pump pushes the water through the UV Sterilizer at a specific flow rate, where the water will come in contact with the UV-C producing light either directly or indirectly via a quartz sleeve.

The UV Light then sterilizes the water by altering the DNA of organic matter as well as “clumping algae” in the water, and it is returned to your tank or pond.

Click on the picture to the left to enlarge

How should I determine what my flow rate should be?

Your flow rate is dependent on the level of sterilization you desire from your tank. The slower the water moves across a UV bulb that is intended primarily for UVC production; the more time UV-C is in contact with the water. The slower the rate, the more sterilization you can achieve. This goes hand in hand with a turnover rate.

What is a turnover rate?

Your turnover rate is the rate at which all your aquarium water is filtered in an hour. For UV Sterilization, you want a turnover rate of at least 1 1/2 times per hour. So if you have a 10 gallon tank, you want a turnover rate of at least 15 GPH. This will achieve level 1 sterilization when combined with the correct flow rate assuming other criteria are met as well.

What are any other criteria for determining the effectiveness of a UV Sterilizer or Clarifier?

The flow rate is the most important factor and along with turnover are easy factors to measure. Nonetheless, while flow rate is probably the most important, probably the next most important factor is not turnover, rather it is water turbidity which includes pre-filtration. With high water turbidity due to poor or no pre-filtration, the flow rate can literally need to be cut in half to achieve rated performance. Or looking at it another way, a UV Sterilizer/Clarifier rated for a 100 gallon aquarium [or pond] might only be effective for a 50 gallon aquarium!

The problem is water turbidity is not as readily measured, thus is not generally included in formulas.

The best way to ensure your water is optimally pre-filtered is to make sure to run the UV Sterilizer after a good filter, including a simple pump pre-filter such as using the AAP Filter Max. Nevertheless most UVs now sold via discount websites as well as brick & mortar stores do not include much of anything when it comes to pre-filtration. When combined with low output medium Pressure lamps and poor design such as the gap between the UV lamp and quartz sleeve and the containment wall; the result is a UV Sterilizer with as low as 1/4 OR LESS of what many formulas rate for flow rate!

Other factors include:

A water temperature between 20 C (68 F) and 40 C (104 F)

A gap of 3 cm or less between the bulb or quartz sleeve and the wall of the unit

A reasonable dwell time, as most low cost, filter equipped UVs, and submersible UVs have poor dwell time

Clarification is about 40-65 gph per watt with a good to excellent UV Sterilizer using a HO low pressure UV lamp. This achieves Green water control in both Aquarium and Pond. This is the most popular application for ponds.

Level 1 Sterilization is about 20-35 gph per watt good to excellent UV Sterilizer using a HO low pressure UV lamp. This helps with Bacteria and some Virus’s. Level One is the most common & recommended aquarium application.

Level 2 Sterilization is about 8-12 gph per watt good to excellent UV Sterilizer using a HO low pressure UV lamp. This helps with Parasites and “Stubborn” Viruses. This is recommended for Swimming Pools (albeit generally impractical) and similar applications. These flow rates for each level are also impacted by water turnover, UV-C Penetration, among other factors.

For economy UV sterilizers with poor dwell time, or using medium pressure UV lamps which produce only 25% of the needed UVC irradiation, the flow rates required can be as much as 4 to 8 times lower which is why most of these $50 or less UVs commonly sold via discounters are really only good for clarification, NOT sterilization.

These flow rates can vary greatly by UV Sterilizer design, with many poor quality UV Sterilizers not being capable of level 1 or 2 sterilization at all, this is particularly common with the many “Hang-On” and submersible models sold for under $50 usd.

How can I achieve these levels?

Levels achieved by a UV Sterilizers are depending on the quality/design of the UV, wattage of UV, and flow rate created by a pump. The correct pump for your tank/pond size and correct sterilizer are required for accurate sterilizing levels. Ball Valves can also be used to slow water flow if pumps gph is higher than required. This is to achieve optimum flow.

Yes and No The use of a UV Sterilizer will NOT directly affect ammonia, nitrites, nitrates, GH, pH, KH; so the use of a UV Sterilizer should not be considered as either a positive or negative to affect these parameters.

However a properly installed and well designed UV Sterilizer will lower organics in the water column, so this can indirectly affect KH levels. As well the use of properly installed and well designed UV Sterilizer can more directly affect the Redox Balance by reacting with oxidants in the water column, which in turns lowers oxidizing stressors to fish or other inhabitants.

Are UV Sterilizers difficult to maintain?

If a Aquarium keeper has a general knowledge of sterilizers and has overcome the first set-up of their UV Sterilizer, it should become very easy to maintain. Other than replacing UV bulbs every 6 months (& possibly cleaning the quartz sleeves if part of the UV), there is no real maintenance that is required. If a UV sterilizer is set up correctly, it will clear up your aquarium/pond in a matter of hours/days and no over action from the keeper is needed. See this web page for high efficiency, true UVC Bulbs: UV Bulbs Page 1 from AAP

Will a UV Sterilizer kill my good bacteria?

The simple answer is NO, but this must be qualified in that this applies to a healthy, cycled aquarium. Even “good” aerobic bacteria found in your bio filters can be a problem when bio loads or other factors cause a “bacterial bloom” in the aquarium water, resulting in a white or grey “cloud”. A UV Sterilizer will kill these bacteria when in the water column (free floating).

However in a healthy established aquarium, aerobic nitrifying bacteria should and will be found in the bio filters, substrate, live rock, etc.; NOT in the water column. Therefore, it is impossible for a UV Sterilizer to remove these beneficial bacterium.

Can you use a UV sterilizer with live rocks in a fish tank

As with the above question, the simple answer is yes. However if you are seasoning ‘dead’ rock such as so-called live rock that was just imported or you are using sterile/quarried calcium based rock (or Aragocrete), it is best to turn off your UV for a few weeks. Once your aquarium and live rock is established, the nitrifying and de-nitrifying bacteria will and should not be in the water column, only in your live rock. So UV Sterilization is safe and in fact should be used 24/7 other than turning off for a couple hours when dosing with live products such as live planktonic algae or infusoria.

Will a submersible UV Sterilizer work as well as an inline out of tank Sterilizer?

This depends upon the design, but in general the answer is an emphatic NO, at least with all under $50 usd units often sold by Amazon or eBay!

The problem is the chamber where the UV-C irradiation/sterilization reacts with the water often has too high a flow rate along with too large a gap between the UV wall and lamp/sleeve, resulting in poor dwell time.

As well, many of these Submersible UV Sterilizers have a very short lifespan due to ballast failures (one, the Killing Machine even requires replacement of the ballast when replacing the UV Lamp). Unfortunately most online reviews (Amazon, etc.) do not reflect expert long term usage and only report initial results. Finally Amazon and other bargain sellers will sell similar models [such as by SunSun], but these are stripped down, without essential pre-filters needed for lowering water turbidity for higher UVC efficiency, as well these models are NOT adjusted for correct UVC flow rates.

AVOID these low cost Hang On UVs, Lift Tube UVs, and small self powered UVs often peddled by those in the aquarium industry that give the industry a “black eye”. About the only only reasonably effective submersible UV Sterilizer is the AAP CUP Series 9 & 13 Watt, along with a few other exact duplicates that include adequate pre-filtration, a low pressure HO UV lamp, and the correct flow rate. Even then these should only be considered an economy UV Sterilizer for those on a budget and desiring simplicity (these still cost more than the non level 1 sterilization models previously noted).

As noted in the last section, an inline UV Sterilizer is best. This should be installed after your filter as the less particles your UV has to get through the better results you will have. Also, installing your UV after your filters allows the filters to have the best possible bio filtration.

What is the best UV to purchase (or what is the strongest UV aquarium or pond steriliser on the market)?

While there are several well designed UV Sterilizers available, most are often far more expensive than the low quality UVs that produce little or no level 1 sterilization of which these should be avoided. A simple tip would be to avoid ANY UV Sterilizer under $50 (US dollars), none of these have even close to adequate dwell times to perform level 1 or level 2 sterilization.

The AAP Terminator UV is a “good” UV Sterilizer, and in fact among the best of the “Compact” UVs, although the popular compact design is not as good a design as the high dwell time straight tube such as the AAP/TMC. Other good compact UVs includes the Tetra, albeit over priced.

Beware of the Jebo, AquaTop, and Turbo Twist, and the plethora of low quality so-called UVs sold on Amazon.com, as despite good marketing, these have poor life spans or little to no level 1 sterilization as per many professionals who have used these units and were consulted for this article.

It is unfortunate that many discount UV Sterilizers sold via Amazon, eBay, etc.; even with the same model model number come with low output medium pressure low output UV lamps/bulbs that have only 1/4 the output of a low pressure HO UV bulb/lamp. What many do not understand is that as a retailer or distributor, one can order these UVs from China at a lower/cheaper price by getting a stripped down version. The end result is a UV or replacement lamp that is good for clarification at best and even then not very good at this either.See the next section about UV lamps/bulbs for more, including excellent references!

Maintenance; How often Should I change the UV bulb/Lamp and which should I use?

Generally speaking for optimum Sterilization the UV Bulb should be changed every six months for an aquarium. For a pond every 12 months in cool climates and six months for warm climates.

As for the replacement bulb itself, this can be a bit more difficult since it seems everyone and their brother are now selling these on the internet (including Amazon & eBay), as well as some Home Improvement Stores. However many, if not most of these bulbs sold at these locations are NOT true low pressure, hot cathode UVC bulbs which provide the optimum output and efficiency, even though one eBay seller in particular has taken to copying the information from another online seller that sells true high output UVC bulbs/lamps.

This is especially problematic with many of the Compact UV Bulbs now sold such as the 5, 9, & 18 Watt UV bulbs, lamps which are sold for less than it cost to produce the better quality true UVC bulbs. If the price seems too good to be true such as $5.99 or even $9.99, you are likely getting a “nail curing” UV lamp, not a true high output low pressure UV lamp/bulb, despite what the sellers eBay or Amazon listing might say. A quick comparison of the UV Bulbs/lamps reveals the difference. Reference: 9 Watt UV Replacement Bulb/Lamp Review

The diagram/picture above demonstrates why is is so important to purchase the correct UV replacement bulb/lamp. Even many new low cost so called UV Sterilizers, which in reality are at best clarifiers are supplied with these lower cost medium pressure UV Bulbs. With the cost just to produce a quality low pressure UV Bulb, chances are ANY UV Sterilizer advertised new for under $50 is going to contain these lower output bulbs.

What to look for?

Price for one, you cannot get a true low pressure hot cathode 9 watt UVC bulb for under $10 (or likely under $12). When the manufactured cost of a HO 9 Watt lamp is $10 usd, a retailer CANNOT sell these for $10 or even $12

Does the seller even claim that their bulb is a low pressure hot cathode UVC germicidal bulb/lamp?

The 9 Watt and 18 Watt UVC germicidal bulbs/lamps now can be found with a patented metal heat shield, which among other things lowers the amount of energy lost to heat and thus increases efficiency. These though can be hard to find in most locations, but are well worth looking for and purchasing due to their extreme high efficiency.

Hi. I have an internal UV filter in my 330 litre tank, its flow rate is 800 LPH and I thought if it failed to work fully as the water passed the UV, as it was a submerged filter the water would come into contact with the UV time and time again and so would get fully treated . After reading several reports by your aquarists I am worried it might not get treated. Cheers Dave.

Thankyou for the brilliant read, One question if I may, can you OVER sterilise pond water causing negative issues for the fish? Im unsure to believe the hype or not. Thank you in advance for your reply Mark

Hi, here is an article I wrote several years ago regarding Hair, Red and Blue Green Algae in any marine quarium. If it ever occurs. It can also be applied to Freshwater Tropical or Goldfish aquariums or ponds.

I don’t know if the following might help, but you could give it a try. It gets rid of (permanently) Red algae in a marine aquarium. Also it fixes up Blue-Green algae in a tropical freshwater aquarium. Great thing is the cure goes all through the filter, gravel, and shell grit, coral sand along with any pipe work or filter material.

So you could give it a go in the fight against hair algae.

Note: I used only one tablet in my marine aquarium 4,000 litres (5 ft deep) marine aquarium and only a single tablet in the 800 litre Freshwater aquarium.

RED ALGAE CURE IN MARINE AQUARIUMS

USE ONE ERYTHROMYCIN TABLET “NOT CAPSULES”

Place Tablet in Aquarium in the Afternoon

Cure should be affected by next morning. Corals and glass will be noticeably cleaner.

Cut back on feeding

Store new water for at least 1 week in darkened container

Or use UV Steriliser.

Many years ago I had an ongoing problem with Red Algae in a 200-gallon Marine Aquarium. No matter what I did it was near impossible to eradicate. The pipe work and filters were also a problem as the spores of the algae were resident in these areas.

Once each week I would climb into the aquarium in a light wet suit, breathing air from a mini aqualung and from a long hose and diving regulator I would spend up to half an hour underwater cleaning the inner part of the aquarium and viewing glass. The algae I cleaned off compounded the problem, as the filters would take it in.

I was to the point of shutting down the marine aquarium. Then one day I was out in my boat doing environmental monitoring of the ocean sea grass beds with a group of marine biologists.

I mentioned about the problem I had been having with the red algae, and told him it had not been possible to eradicate. Anyway he told me to try using a single ERYTHROMYCIN TABLET “NOT CAPSULES”. Then do a 60% water change after 1 week. Also do not feed the fish for a period of one week starting from the time you use the ERYTHROMYCIN TABLET.

Anyway I got a packet of tablets from the Vets. I added it to the aquarium in the evening. The aquarium rocks, coral and glass had quite a bit of the algae covering it looking like red velvet.

Anyway the next morning when I arose I looked towards the aquarium. I could not believe my eyes. All traces of the red algae had disappeared. The aquarium was spotlessly clean.

The red algae problem never returned. So I never got the chance to use the rest of the ERYTHROMYCIN TABLETS. I have not had to clean the inside of the aquarium or viewing glass in over two years.

I know that some aquarium cures do contain ERYTHROMYCIN, If there is one in your local pet shop stating that it will address the problem of red or other algae’s in the aquarium, it may also work for you.

Added to this once the algal problem was cured, to make sure no algal spores where introduced from raw seawater I installed a UV Steriliser.

I have a 30 gallon tank. I have a 9W Deep Blue Pro Sterilizer set up in line after a Fluval 405 filter. Right now, I have a tee right before the sterilizer so most of the flow goes into the sterilizer. The gph is 100. The turnover is about 3 x per hour. The 100 gph is with a fairly clean filter. I assume the gph drops as the filter collects waste but I haven’t measured that. (I clean the Fluval once a month.) I can take away the tee and have all the flow go into the sterilizer. This would raise my gph to 150 and a turn over rate of about 5.

Is it better to have a lower gph (greater sterilization-level 2) but a turn over of 3 or a higher gph w/ a turnover of 5 (level 1 sterilization? Thank U

Hi there I have a 37 gal. tank using an undergravel filter system powered by a power-head unit instead of a pump air lift system. My question is can a UV be used on the opposite side of the tank without disrupting the filtration flow?

Your email address will not be published. Required fields are marked *

Comment

Name *

Email *

Website

Search for:

Adverts 2

What is Fish Beginner’s Mission?

Our mission as a primarily Computer Tech hosting company is to take the most in depth and accurate content, along with suggested products and make it understandable for beginners, but still be relevant to advanced fish keepers as well.

Readers will note that we will reference often very long, in depth, and scientifically accurate web content from where we simplify the content. Our emphasis is science based, not popularity based information, so if you read of methods or products mentioned here that are not as often noted in some popular, but often inaccurate websites, forums, or blogs; please read the references cited here and apply common sense logic.